For mobile radio communication devices such as User Equipment (UE) handsets operating in relation to mobile communication networks, various security-related procedures arise at the time of seeking network connection, whether at the time of initial connection or when the UE is required to handover from one network to another. Such handover procedures can involve handovers between different network technologies particularly as communication systems and there underlying technologies evolve.
Security algorithms are generally provided in order to achieve, and maintain, ongoing secure communication between the UEs and the network and it is quite common for the Core Network (CN) to provide the required security algorithm on the basis of the security capabilities of the UE.
Problems and potential limitations have however been found to arise due to the potential for differences in security algorithms arising in particular, subsequent to a change in algorithm due to an upgrade such that one of a UE or a network device is not fully upgraded for use solely with a new algorithm.
The security of ongoing data transfer can then be compromised through the ongoing use of the possibly now out of date, or unsupported and unwanted algorithm.
Various network systems and devices are known relating to security issues and, in particular, security algorithm creation and negotiation such as, for example, found in Chinese Patent Applications CN10124236G, CN101374153, CN101222320 and U.S. patent application US 2006/294575.
While aspects of network security are covered by these earlier applications, none seeks to address the problems now identified and as overcome by the present invention concerning the use of old and potentially unsupported algorithms, and due to the differences in security capabilities that can arise as security algorithms are updated.